Delphi DLL GMail: Search for Messages with Subject Containing a Word

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Return messages matching the specified query. See https://support.google.com/mail/answer/7190?hl=en for additional information about search operators. This example searches for all emails having the whole word "ADVChina" in the subject.

Documentation: https://support.google.com/mail/answer/7190?hl=en

CURL Command

curl -X GET https://www.googleapis.com/gmail/v1/users/me/messages?q=subject:ADVChina \
    --header "Authorization: Bearer GMAIL_TOKEN"

Delphi DLL Example

var
rest: HCkRest;
success: Boolean;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
sbResponseBody: HCkStringBuilder;
respStatusCode: Integer;
jsonResponse: HCkJsonObject;
i: Integer;
count_i: Integer;
resultSizeEstimate: Integer;
id: PWideChar;
threadId: PWideChar;

begin
rest := CkRest_Create();

//  URL: https://www.googleapis.com/gmail/v1/users/me/messages?q=subject:ADVChina
bTls := True;
port := 443;
bAutoReconnect := True;
success := CkRest_Connect(rest,'www.googleapis.com',port,bTls,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add('ConnectFailReason: ' + IntToStr(CkRest_getConnectFailReason(rest)));
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

CkRest_AddHeader(rest,'Authorization','Bearer GMAIL_TOKEN');

sbResponseBody := CkStringBuilder_Create();
success := CkRest_FullRequestNoBodySb(rest,'GET','/gmail/v1/users/me/messages?q=subject:ADVChina',sbResponseBody);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;
respStatusCode := CkRest_getResponseStatusCode(rest);
if (respStatusCode >= 400) then
  begin
    Memo1.Lines.Add('Response Status Code = ' + IntToStr(respStatusCode));
    Memo1.Lines.Add('Response Header:');
    Memo1.Lines.Add(CkRest__responseHeader(rest));
    Memo1.Lines.Add('Response Body:');
    Memo1.Lines.Add(CkStringBuilder__getAsString(sbResponseBody));
    Exit;
  end;

jsonResponse := CkJsonObject_Create();
CkJsonObject_LoadSb(jsonResponse,sbResponseBody);

//  See the Online Tool for Generating JSON Parse Code

resultSizeEstimate := CkJsonObject_IntOf(jsonResponse,'resultSizeEstimate');
i := 0;
count_i := CkJsonObject_SizeOfArray(jsonResponse,'messages');
while i < count_i do
  begin
    CkJsonObject_putI(jsonResponse,i);
    id := CkJsonObject__stringOf(jsonResponse,'messages[i].id');
    threadId := CkJsonObject__stringOf(jsonResponse,'messages[i].threadId');
    i := i + 1;
  end;

CkRest_Dispose(rest);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jsonResponse);

Sample JSON Response Body

{
  "messages": [
    {
      "id": "166e50fed0b9b0cb",
      "threadId": "166e50fed0b9b0cb"
    },
    {
      "id": "166c12e5fee013fe",
      "threadId": "166c12e5fee013fe"
    },
    {
      "id": "1669cc9a926bb8c1",
      "threadId": "1669cc9a926bb8c1"
    },
    {
      "id": "16678c485e7f0a0c",
      "threadId": "16678c485e7f0a0c"
    }
  ],
  "resultSizeEstimate": 4
}